Simple calculations

Show data

Plot data

Things in R

• Values: 1, "Dresden", "2024-12-10"
• Objects: x <- c(22/7, 0.99, 3)
• Functions: round(x, digits = 3

Data science workflow

In the console…

Let’s use this as a calculator.

In the console (ctd)…

Let’s learn how to use a function. For this, we need to add arguments to the function call.

?head
?names
?plot

In the R script…

Let’s have a look at a data set: mtcars. What is it about?

To execute a line of code, use Shift + Enter.

Excursion: Classes

• numeric (1.34, -10.6)
• integer (1, -99)
• character ("hello", "world")
• NAs: “not assigned”
• factors

Pop quiz

What class does this result have?

Pop quiz – NAs

What’s the result?

Let’s plot this data set, specifically the columns mpg and hp. To access them, we have to put a $ between the name of the data set and the name of the column. It will show up in the Plots pane.

Comments

We’re still in the R script. What if we want to explain to others (or our future self) what we intended with this code?

Assigning (<-)

What if we want to create a new object? Easy:

Packages

What if we want more functions? We install packages, which contain functions. We install them once (in the console).

We can then load them (once per script).